"Tony Stark is not going to be involved in any of the movies until ['Avengers']," the director recently told Los Angeles radio station KROQ's "The Kevin and Bean Show."

Jon added that it'll be "very interesting" to see how the 2012-due team-up film ties together the growing big screen world of Marvel superhero mythology, which also includes 2008's "The Incredible Hulk."

"I'm not sure where 'The Avengers' goes," Jon said. "There is no shooting draft written yet. It's gonna be a big undertaking for Marvel… All that has to inform one unified vision in 'The Avengers.' It's a very exciting prospect."

Up next for Jon is another action romp, "Cowboys and Aliens," which the director said may be shot in 3D – and could be a test-run for a 3D "Iron Man" sequel.

"We are looking at what the gear can hold up to because we are shooting in the desert, which has never been done before with this type of gear," he said. "We are discussing whether or not we want to do it on the next ['Iron Man'] film."